cis,cis-Muconic acid isomerization and catalytic conversion to biobased cyclic-C₆-1,4-diacid monomers

Abstract

Renewable terephthalic and 1,4-cyclohexanedicarboxylic acids can be produced from biomass via muconic acid using a combination of biological and chemical processes. In this conversion scheme, cis,cis-mucononic acid is first obtained by fermentation using either sugar or lignin monomers as a feedstock. The diunsaturated cis,cis-diacid is then isomerized to trans,trans-muconic acid, reacted with biobased ethylene through Diels-Alder cycloaddition, and further hydrogenated or dehydrogenated to yield the desired 100% renewable cyclic dicarboxylic acid. The isomerization of cis,cis-to trans,trans-muconic acid represents the main bottleneck in this process due to undesired side reactions that promote ring closing to form lactones. Therefore, new technologies for the selective isomerization of muconic acid are urgently needed. Here, we studied the corresponding reaction kinetics to elucidate the mechanisms involved in both the isomerization and cyclization reactions with the objective to identify conditions that favor the selective formation of trans,trans-muconic acid. We demonstrate that the reactivity of muconic acid in aqueous media strongly depends on pH. Under alkaline conditions, cis,cis-muconic acid is deprotonated to the corresponding muconate dianion. This species is stable for extended periods of time and does not isomerize. Conversely, cis,cis-muconic acid readily isomerizes to its cis,trans-isomer under acidic conditions. Prolonged heating further triggers the intramolecular cyclizations through reaction of the carboxylic acid and alkene functionalities. The formation of the muconolactone and its dilactone is kinetically favored over the isomerization to trans,trans-muconic acid over a broad range of conditions. However, strategies involving the chelation of the carboxylates with inorganic salts or their solvation using polar aprotic solvents were found to hamper the ring closing reactions and allow the isomerization to trans,trans-muconic acid to proceed with high selectivity (88%). The obtained compound was further reacted with ethylene and hydrogenated to 1,4-cyclohexanedicarboxylic acid, an important monomer for the polyester and polyamide industries. Disciplines Biochemical and Biomolecular Engineering | Catalysis and Reaction Engineering | Chemical EngineeringComments This is a manuscript of an article published as Carraher, Jack M., Toni Pfennig, Radhika G. Rao, Brent H. Shanks, and Jean-Philippe Tessonnier. "cis, cis-Muconic acid isomerization and catalytic conversion to biobased cyclic-C 6-1, 4-diacid monomers." Green Chemistry 19, no. 13 (2017) Renewable terephthalic and 1,4-cyclohexanedicarboxylic acids can be produced from biomass via muconic acid using a combination of biological and chemical processes. In this conversion scheme, cis,cis-mucononic acid is first obtained by fermentation using either sugar or lignin monomers as a feedstock. The diunsaturated cis,cis-diacid is then isomerized to trans,trans-muconic acid, reacted with biobased ethylene through Diels-Alder cycloaddition, an...

Bioderived Muconates by Cross‐Metathesis and Their Conversion into Terephthalates

“…The X‐ray diffraction patterns of as‐synthesized and commercial dimethyl muconate differed only in the presence of additional small diffraction peaks coming from the tamuate impurity in the synthesized dimethyl muconate product. Analysis of the product by 1 H NMR and 13 C NMR spectroscopy also confirmed the chemical structure of as‐synthesized trans , trans ‐dimethyl muconate and the triene impurity . 1 H NMR (400 MHz, CD 3 OD, trans , trans ‐dimethyl muconate): δ =7.35 (dd, 2 H), 6.30 (d, 2 H), 3.75 ppm (s, 6 H); 13 C NMR (400 MHz, CD 3 OD, trans , trans ‐dimethyl muconate): δ =51.6, 128.4, 141.6, 167.1 pm; 1 H NMR (400 MHz, CD 3 OD, dimethyl tamuate): δ =7.38 (dd, 2 H), 6.79 (dd, 2 H), 6.13 (d, 2 H), 3.76 ppm (s, 6 H).…”

Bio Adipic Acid Production from Sodium Muconate and Muconic Acid: A Comparison of two Systems

“…The so produced Na‐Muc is purified to produce MA which is catalytically hydrogenated to AdA. The purification of Na‐Muc involves the use of highly acidic environment that isomerizes the cis,cis substrate to the trans,trans MA compound, but it is necessary for the obtainment of a substrate with a purity >98 % . Also, it has been extensively proven that both cis,cis and cis,trans ‐MA tend to isomerize to trans,trans ‐MA (t,t‐MA) in the presence of metals that strongly bind hydrogen molecules .…”

Iodine‐Catalyzed Isomerization of Dimethyl Muconate

“…Rorrer uncatalyzed. [21] Through solvent screening, a ttMA yield of up to 55 %w as achieved in DMSO. Experimentally,t he isomerization of the diacid, ccMA, ando ft he methyl ester, ccDMM,h as been investigated.…”

“…The isomerization of ccMA to ttMA was recently studied using as olvent-catalyzed system. [21] Through solvent screening, a ttMA yield of up to 55 %w as achieved in DMSO. Similar yields were targeted in aqueous media through addition of lanthanum(III) salts and pH control.…”